Thread by @firefoxx66

Recently I've heard from collaborators in the US & Europe that #Enterovirus #D68 #EVD68 cases are on the rise.

EV-D68 is what I worked on pre-pandemic, & hope to go back to.
A significant autumn 2022 wave has been a recent concern.

So what is D68 & what might this mean?

1/17

#EVD68 is a Picornavirus - a diverse family of viruses. And Enteroviruses are pretty diverse themselves: from Poliovirus, which can cause serious neurological illness, to Rhinovirus - what's behind the common cold 🤧 (and even more in between).

2/17

One of the most notable things about #EVD68 is that in Europe & North America it's historically had biennial autumn outbreaks: in 2014, 2016, & 2018. Also predicted in 2020... but that didn't happen due to pandemic!
Following that pattern, 2022 would be an outbreak season🗓️

3/17

Usually, #EV68 causes mild respiratory symptoms - usually diagnosed in young children - but these can sometimes be more severe.

In the last decade or so, EV-D68 has also been linked to #AFM - acute flaccid myelitis - partial or complete paralysis. Quite concerning.

4/17

I like to say #EVD68 is a virus nobody's heard of - but everyone's had! 🤷🏻‍♀️

We can see antibody titres against D68 go up through childhood (= prev infection), & find them in >98% adults.
In general they seem to be long-lived, but we don't know how complete protection is.

5/17

I can go on a lot more about #Enterovirus #D68 #EVD68 (& I will, in future threads).
But why do we care _now_? With monkeypox & SARS-CoV-2... why am I writing today about this little virus? 🤔

Well - because the pandemic made things a bit weird for all respiratory viruses.

6/17

Particularly in 2020, restrictions to limit #SARSCoV2 (lockdowns, but also closures, masks, awareness, less social activity) _also_ limited all the usual respiratory viruses - including #EVD68

Right up through when we were predicting our next D68 outbreak.

7/17

That doesn't sound so bad - & it wasn't while those viruses stayed away (though notice how quickly Rhino bounced back 😆). But, this potentially led to many children (& adults?) not getting exposed to #EVD68 when they usually would have been.

8/17

This may mean an 'immunity gap' for #EVD68 - that more children (in particular) are susceptible to #EVD68 than during a 'usual' outbreak, since circulation was considerably lower.

This was outlined really well by Nguyen-Tran et al. thelancet.com/journals/lanmi…

9/17

And why might that matter?

Well, it might mean a much larger outbreak: there are more totally-naïve (perhaps also more not-naïve-but-less-well-protected) individuals present.
This could mean, in particular, extra pressure on hospitals & paediatric units this autumn.

10/17

Further, we don't fully understand whether a delayed 1st exposure may have different symptom presentation/outcome. We haven't seen signs of this previously, but with enough cases, even a slight shift could mean even more hospital pressure, severity, and/or AFM.

11/17

This is another a concrete reminder why we should not get complacent about #SARSCoV2 this autumn either!
Any burden it adds to hospitals isn't helpful for any other "post-pandemic restriction" resurgence we see in other respiratory viruses!

12/17

Of course, we don't yet know how things may pan out in the USA or Europe. But I do think, with the lack of #EVD68 circulation in 2020, 2022 being a predicted outbreak year, & these early reports of a rise -- we should be prepared for an outbreak.

13/17

On my end, I'm hoping to update the #Enterovirus #D68 #EVD68 builds that I maintain at @nextstrain, ready to pull in new sequences as they come.
I'll post links as soon as I can make that happen!

14/17

I also hope to help provide sequencing of #EVD68 samples from here in #Switzerland, thanks to my recent award (see next tweet).
This will help us take a closer look at patterns we see: ages impacted, symptoms, genetic changes & geographical spread!

15/17

You can get the 3-minute-summary of this thread from my presentation for the Johanna Dürmüller-Bol @DBMR_UniBe award in July:

https://twitter.com/firefoxx66/status/1544930045214752768

16/17

I'm very grateful to everyone I have had the pleasure to collaborate with so far on #EVD68, & those I hope to in future!
@ENPEN_ESCV @Jan_Albert_ @robert_dyrdak @AppliedMicrobi2 @RametteA @HarvalaHeli @kmess44 Kim Benschop, Maggie Pires Simoes & many more!

17/17

Stay tuned for more #EVD68 threads in the future!

18/17